Abstract: In some aspects, techniques and systems for modeling fluid flow are described. Pressure gradient values for respective nodes of a one-dimensional flow model are computed. The nodes represent locations of fluid flow along a flow path, and the pressure gradient values are computed based on an approximation of the flow velocity at a point on the flow path. A pressure drop between two opposite ends of the flow path is calculated based on the pressure gradient values. An improved approximation of the flow velocity for the point on the flow path is calculated based on a difference between the calculated pressure drop and a pressure drop boundary condition.

Abstract: Systems, methods, and software can be used to analyze microseismic data from a fracture treatment. In some aspects, stored data associate a fracture plane with a first plurality of microseismic events from a fracture treatment of a subterranean region. Additional stored data indicate an ordering of a second, different plurality of microseismic events from the fracture treatment. One of the second plurality of microseismic events is selected based on the ordering, and the fracture plane is updated based on the selected microseismic event.

Abstract: Systems, methods and software can be used for analyzing microseismic data collected from a fracturing treatment of a subterranean zone. In some aspects, a plurality of basic planes are each defined from a subset of the microseismic data and each have an orientation relative to a common axis. Clusters of orientations of the basic planes previously identified adaptively based on the extent of variation in the orientations can be updated with new data. The number of orientations associated with each of the clusters is then identified.

Abstract: Systems, methods, and software can be used to identify fracture planes in a subterranean zone. In some aspects, data representing locations of microseismic events associated with a subterranean zone are received. Fracture plane parameters are calculated from the locations of the microseismic events. The fracture plane parameters are calculated based on a sum of weighted terms, and each of the weighted terms includes a weighting factor that decreases with a distance between at least one of the microseismic events and a fracture plane defined by the fracture plane parameters.

Abstract: Systems, methods and software can be used for analyzing microseismic data from a subterranean zone. In some aspects, a plurality of basic planes are each defined from a subset of the microseismic data and each have an orientation relative to a common axis. Clusters of orientations of the basic planes are identified adaptively based on the extent of variation in the orientations. The number of orientations associated with each of the clusters is then identified.

Abstract: Systems, methods, and software can be used to identify properties of fractures in a subterranean zone. In some aspects, a basic plane orientation is determined for each of a plurality of basic planes. The basic planes are defined by coplanar subsets of microseismic event data from a fracture treatment of a subterranean zone. The quantity of the basic plane orientations in each of a plurality of ranges is calculated. In some implementations, a histogram is displayed to indicate the quantity of basic plane orientations in each of the orientation ranges. A dominant fracture orientation is identified for the subterranean zone based on one or more of the identified quantities.

Abstract: Systems, methods, and software can be used to calculate fracture stratigraphy of a subterranean zone. In some aspects, microseismic event data associated with a fracture treatment of a subterranean zone are received, and the subterranean zone includes multiple subsurface layers. A filter is used to select a subset of the microseismic event data corresponding to fractures in a particular subsurface layer. Fracture stratigraphy is calculated for the particular subsurface layer from fracture planes associated with the selected subset of the microseismic event data.

Abstract: Systems, methods, and software can be used to analyze microseismic data from a fracture treatment. In some aspects, fracture planes are identified based on microseismic event data from a fracture treatment of a subterranean zone. Each fracture plane is associated with a subset of the microseismic event data. Confidence level groups are identified from the fracture planes. Each confidence level group includes fracture planes that have an accuracy confidence value within a respective range. A graphical representation of the fracture planes is generated. The graphical representation includes a distinct plot for each confidence level group.

Abstract: Systems, methods, and software can be used to determine a confidence value for a fracture plane. In some aspects, a subset of microseismic events associated with a fracture treatment of a subterranean zone are selected. Confidence in associating the selected subset of microseismic events with a common fracture plane is determined. The confidence can be determined, for example, based on the number of microseismic events in the subset, a location uncertainty for each microseismic event in the subset, a moment magnitude for each microseismic event in the subset, a distance between each microseismic event and a fracture plane fitted to the microseismic events, an orientation of the fracture plane fitted to the microseismic events, or a combination of these and other factors.

Abstract: Systems, methods, and software can be used to update fracture planes based on microseismic data from a fracture treatment. In some aspects, a first fracture plane is updated based on a microseismic event in a microseismic data set associated with a fracture treatment. The first fracture plane is one of multiple previously-generated fracture planes. A second, different fracture plane of the previously-generated fracture planes is updated to account for information generated by updating the first fracture plane based on the microseismic event.

Abstract: Systems, methods, and software can be used to analyze microseismic data from a fracture treatment. In some aspects, data for a new microseismic event are from a fracture treatment of a subterranean zone. An updated parameter for a fracture plane is calculated. The fracture plane was previously generated based on data for prior microseismic events. The updated parameter calculated is calculated based on the data for the new microseismic event and the data for the prior microseismic events. A graphical representation of the fracture plane is displayed based on the updated parameter.